112 
EXPOSITION AT VIENNA. 
to be strong. Some perforated curved bricks like the 
figure, 16x4x2 inehes, were also in tho collection. 
Curved chanuel tiles 
for open drains or 
gutters, by the same 
exhibitor, merit at 
tention. These are 
made in three parts, 
fitted together longi- 
tudinally, and are of 
several sizes, all of 
tliem with large open- 
iugs in the body, effecting a great 
saving of material and givin«- light- 
o o C 1 o 
ness and strength. 
Dovetailed Beicks.—France. 
Mr. E. Pavy, of Chateau du Claveau, near Mezikres-en- 
Brenne (Indre), France, exhibited a novel invention, for 
which he bas taken out a patent in France, consisting of 
bricks fornied with dovetailed recesses in each end, so that 
two bricks may be locked fogether by a third piece which fits 
into the two opposite openings. 
The dimensions of the ordinary bricks are stated as 
0 m -25xO m -12X0 m -06, which is about 9|-x4|x2f inehes. 
The locking-piece or dovetail is about five inehes loug. 
The inventor claims for these bricks that they permit of the 
rapid construction of walls of a single course having not only 
lightness but great strength ; or of thick walls, of two courses 
of the brick, with an air-space between, giving greater 
strength than is obtained in ordinary constructions using two 
or three times as much material, and consequently requiring 
more carting, more time, labor and expense. The circular 
brick are designed for round towers and chimneys, and ap- 
pear to be favored by the exhibitor as an attraotive mode of 
finishing the corners uf constructions, an ideal house being 
figured by him with a round tower at each corner. 
Window frames of oak, or iron, are made with a dove 
tailed recess in the sides, into which the small locking-piece 
is fitted, thereby forming a tight joint and holding the